Sure, here's an example of a simple implementation of the game Flappy Bird using HTML and JavaScript:
This code will display a canvas element where the game will be rendered. The player controls the bird by clicking on the screen, making it jump. The objective is to navigate the bird through the gaps between the green obstacles. The score increases every time the bird passes an obstacle. If the bird collides with an obstacle, the game is over, and the score is displayed in an alert dialog. The game will also restart automatically.